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101.
The Multiprocessor Bandwidth Inheritance (M-BWI) protocol is an extension of the Bandwidth Inheritance (BWI) protocol for symmetric multiprocessor systems. Similar to Priority Inheritance, M-BWI lets a task that has locked a resource execute in the resource reservations of the blocked tasks, thus reducing their blocking time. The protocol is particularly suitable for open systems where different kinds of tasks dynamically arrive and leave, because it guarantees temporal isolation among independent subsets of tasks without requiring any information on their temporal parameters. Additionally, if the temporal parameters of the interacting tasks are known, it is possible to compute an upper bound to the interference suffered by a task due to other interacting tasks. Thus, it is possible to provide timing guarantees for a subset of interacting hard real-time tasks. Finally, the M-BWI protocol is neutral to the underlying scheduling policy: it can be implemented in global, clustered and semi-partitioned scheduling. After introducing the M-BWI protocol, in this paper we formally prove its isolation properties, and propose an algorithm to compute an upper bound to the interference suffered by a task. Then, we describe our implementation of the protocol for the?LITMUS RT real-time testbed, and measure its overhead. Finally, we compare M-BWI against FMLP and OMLP, two other protocols for resource sharing in multiprocessor systems. 相似文献
102.
Matthew J. Graham S. G. Djorgovski Ashish Mahabal Ciro Donalek Andrew Drake Giuseppe Longo 《Distributed and Parallel Databases》2012,30(5-6):371-384
Astronomy has been at the forefront of the development of the techniques and methodologies of data intensive science for over a decade with large sky surveys and distributed efforts such as the Virtual Observatory. However, it faces a new data deluge with the next generation of synoptic sky surveys which are opening up the time domain for discovery and exploration. This brings both new scientific opportunities and fresh challenges, in terms of data rates from robotic telescopes and exponential complexity in linked data, but also for data mining algorithms used in classification and decision making. In this paper, we describe how an informatics-based approach—part of the so-called “fourth paradigm” of scientific discovery—is emerging to deal with these. We review our experiences with the Palomar-Quest and Catalina Real-Time Transient Sky Surveys; in particular, addressing the issue of the heterogeneity of data associated with transient astronomical events (and other sensor networks) and how to manage and analyze it. 相似文献
103.
Michele?RisiEmail author Giuseppe?Scanniello Genoveffa?Tortora 《Formal Aspects of Computing》2012,24(3):307-330
In this paper we present an approach to automate the architecture recovery process of software systems. The approach is built
on information retrieval and clustering techniques, and, in particular, uses Latent Semantic Indexing (LSI) to get similarities
among software entities (e.g., programs or classes) and the k-means clustering algorithm to form groups of software entities
that implement similar functionality. In order to improve computational time in the context of the software evolution and
then reduce energy waste, the architecture recovery process can be also applied by using fold-in and fold-out mechanisms that,
respectively, add and remove software entities to the LSI representation of the understudy software system. The approach has
been implemented in a prototype of a supporting software system as an Eclipse plug-in. Finally, to assess the approach and
the plug-in, we have conducted an empirical investigation on five open source software systems implemented using the programming
languages Java and C/C++. In the investigation special emphasis has been also given to the effect of using the fold-in and
fold-out mechanisms. 相似文献
104.
Maria Letizia Corradini Valentino Fossi Andrea Giantomassi Gianluca Ippoliti Sauro Longhi Giuseppe Orlando 《Control Engineering Practice》2012,20(8):816-822
This paper presents a robust discrete-time sliding mode control coupled with an uncertainty estimator designed for planar robotic manipulators. Experimental evidence shows satisfactory trajectory tracking performances and noticeable robustness in the presence of model inaccuracies, disturbances and payload perturbations. Ultimate boundedness of the tracking errors is proved, as well as boundedness of the estimation error with arbitrary precision. 相似文献
105.
Reinhard Miller Dmitri Grigoriev Jürgen Krägel Alexander V. Makievski Valentin B. Fainerman Volodymyr I. Kovalchuk Libero Liggieri Francesca Ravera Michele Ferrari Eva Santini Giuseppe Loglio Victoria Dutschk Thodoris Karapantsios 《Microgravity science and technology》2006,18(3-4):104-107
The utilisation of particle-surfactants nanostructures as stabilising agents represents today the technologic and scientific frontier in the stabilisation of liquid films in emulsion and foams. This topic will be addressed by the proposal STEFAN (STabilisation of Emulsions and FoAms by Nanoparticles), proposed by European groups in the framework of the ESA AO-2004 for Life and Physical Sciences and Applied Research projects Similarly to what can be observed for surfactant-stabilised emulsions and foams, microgravity provides ideal conditions for the investigation of the hierarchy of involved objects: interfacial layer, liquid film, dispersed systems foam or emulsion. Microgravity experiments are planned by refurbishing the Experimental Container FASES for the ISS Fluid Science Laboratory and the facility FASTER for the European Drawer Rack, already under development in existing research programmes. Here the scientific guidelines of the project are presented together with examples and preliminary results on the effect of nano-particle-surfactant structures adsorbed at liquid interfaces. First experimental results have been achieved for particle monolayers at the water/air interface and a thermodynamic model was derived to describe the obtained surface pressure-area isotherms. 相似文献
106.
Dania Esposito Andrea Margonelli Emanuela Pace Maria Teresa Giardi Cecilia Faraloni Giuseppe Torzillo Alba Zanini 《Microgravity science and technology》2006,18(3-4):215-218
Photosynthetic microorganisms are expected to be useful to maintain an oxygenic atmosphere and to provide biomass for astronauts in the International Space Station as well as in future long-term space flights. However, fluxes of complex ionizing radiation of various intensities and energies make space an extreme environment for the microorganisms, affecting their photosynthetic efficiency. To automatically monitor the photosynthetic Photosystem II (PSII) activity of microorganisms under space conditions an optical biosensor, which utilizes chlorophyll fluorescence as biological transduction system, was built; the PSII activity was monitored by the biosensor during balloon flights at stratospheric altitudes of about 40 km. The effect of space stress on quantum yield of PSII varied among the tested species depending on the growth light conditions at which they were exposed during the flights. 相似文献
107.
Felice Strollo Lia Pecorelli Giovanna Strollo Massimo Morè Giuseppe Riondino Maria Angela Masini Bianca Maria Uva 《Microgravity science and technology》2006,18(3-4):226-229
A significant reversible decrease in testosterone (T) has been associated with microgravity in male rodents and humans. Urinary T excretion increases in primates under hypergravity. Hypogonadism is somehow related to abnormally high levels of leptin (L), a hormone produced by the adipose tissue which has been found to increase under microgravity simulation conditions like head down bed rest (HDBR). The aim of this study was to assess hemodynamic and pituitary-adrenal and -gonadal adaptation to an acute HDBR test to be eventually used on a routine basis to get better prepared to next space flights. The Authors performed a 1 hour ?12° HDBR in 6 male and 6 female volunteers who underwent heart rate and blood pressure measurement together with a blood draw three times at 30 min intervals from the start to the end of the test for L, T, estradiol (E2), LH, androstenedione (A), cortisol (F), ACTH. 12 age- and sexmatched control subjects followed the same protocol except for keeping the sitting position all the time. According to the ANOVA for repeated measures, no changes occurred in L, T, E2 or LH whereas A, F and ACTH significantly decreased independently of gender. During HDBR systolic blood pressure decreased in both genders, diastolic blood pressure decreased significantly only in men and HR showed a more clear-cut decrease in women than in men. As a conclusion, such an acute steep-slope HDBR protocol may be efficiently used to testing immediate individual haemodynamic or adrenal response to microgravity but is not suitable for studies concerning gonadal adaptation. 相似文献
108.
In this paper we present the results of XPS study of the surface chemistry of L-CVD SnO2 thin films onto Si(100) before and after subsequent additional oxidation. Moreover, the ageing effect was also studied in order to check the influence of ambient oxidation. As-deposited L-CVD SnO2 thin films exhibit evident nonstoichiometry with the relative concentration [O]/[Sn] equal to 1.29 ± 0.1. After in situ oxidation at high temperature (800 K) the relative concentration [O]/[Sn] increases to 1.95 ± 0.05 which corresponds to the almost stoichiometric SnO2. Almost the same relative concentration [O]/[Sn] of L-CVD SnO2 thin films has been obtained after long term exposure to air. The oxidation states of L-CVD SnO2 thin films in both cases were confirmed by the shape analysis of corresponding XPS O1s and Sn3d5/2 peaks using the decomposition procedure. For the as-deposited L-CVD SnO2 thin films a mixture of SnO and SnO2 was observed, while for the oxidized L-CVD SnO2 thin films the domination of SnO2 was determined. 相似文献
109.
Alexander V. Makievski Volodymyr I. Kovalchuk Jürgen Krägel Madine Simoncini Libero Liggieri M. Ferrari Piero Pandolfini Giuseppe Loglio Reinhard Miller 《Microgravity science and technology》2005,16(1-4):215-218
The present work shows the first experimental and theoretical results for investigations on the rheology of liquid films. The experiments are planned to be performed under microgravity conditions. This environment will allow forming films of different thickness, which is impossible under ground conditions due to drainage. Then the films are forced to harmonic oscillations of the film area so that the film elasticity can be measured as a function of frequency. The presented theoretical model demonstrates the main relationships to be solved under corresponding boundary conditions 相似文献
110.
Michela Mortara Giuseppe Patané Michela Spagnuolo Bianca Falcidieno Jarek Rossignac 《Algorithmica》2003,38(1):227-248
Tools for the automatic decomposition of a surface into shape
features will facilitate the editing, matching, texturing,
morphing, compression and simplification of three-dimensional shapes. Different
features, such as flats, limbs, tips, pits and various blending
shapes that transition between them, may be characterized in terms
of local curvature and other differential properties of the
surface or in terms of a global skeletal organization of the
volume it encloses. Unfortunately, both solutions are extremely
sensitive to small perturbations in surface smoothness and to
quantization effects when they operate on triangulated surfaces.
Thus, we propose a multi-resolution approach, which not only
estimates the curvature of a vertex over neighborhoods of variable
size, but also takes into account the topology of the surface in
that neighborhood. Our approach is based on blowing a spherical
bubble at each vertex and studying how the intersection of that
bubble with the surface evolves. We describe an efficient approach
for computing these characteristics for a sampled set of bubble
radii and for using them to identify features, based on easily
formulated filters, that may capture the needs of a particular
application. 相似文献